How Should I Terminate My Fiber Optic Cable
In today’s day and age, we are more connected than ever. And we expect it.
At the work place we are attending virtual trainings on the latest technologies and we are connecting across the globe with our colleagues in real-time meetings – with just the click of a button.
When we leave work, we are going home using app-based scooters and bicycles that only needs the swipe of a cell phone. And if taking a highway home, you no longer search for change at a toll booth but instead you drive through a toll lane that scans and charges your account as you drive underneath it.
And it doesn’t stop at home. We are answering emails, while streaming Ultra HD video on our smart TV’s, all while having the latest super hero flick downloading on our tablet to watch on an upcoming business trip.
With the ever-increasing demand for the bandwidth needed to meet today’s expectations; how we design, install, and maintain our fiber optic networks must evolve with that same demand. In particular, the methods used to terminate, or connect, the ends of our fiber optic networks has evolved in the past 20 years quite drastically; starting with hand-polishing a ferrule with films and epoxies to achieve a finished termination. Hand epoxy polishing gave you a good, epoxy-cured connection but can be time consuming, and it took certain skill sets to achieve a good ferrule polish. Epoxy terminations lead to Mechanical Terminations which is the mechanical mating of fibers with the use of specific hand tools, v-groove alignment, and index matching gel to bridge the air gap between fibers. The benefits of using a factory-polished ferrule and the mechanical termination offered a time saving from traditional hand-polishing and allowed even some of the most novice of technicians the ability of putting a quality connector on in the field. As optical fusion splice machines and fusion splicing technology improved, technicians can now fusion splice a pigtail, a length of cable factory terminated on a single end, to a field cable that has been newly pulled or an old cable that needs to be repaired.
More importantly than any convenience of use though, is the performance of the termination. To enjoy some of the luxuries of connectivity mentioned before, we need a stronger optical signal to go farther than ever. Insertion Loss (IL) is a measurement of the optical power that is lost through a mated pair in decibels (dB). To compare the performance in IL of the three main termination methods, hand epoxy can typically range from .20dB - .75dB depending on installer. A typical mechanical style termination IL is 0.50dB, with loss accumulating from both the air gap of a mated pair, and the alignment of the fiber stub to your field fiber. Fusion splicing a pigtail or connector, is going to give your lowest loss of light through termination. Average fusion splice termination IL is .02dB - .05dB of loss through the splice, for a total of typical .20dB IL from your termination. By fusion splicing a connector in your network you are performing that much better in regards of your signal getting from source to receive.
Another important factor of your termination is how much light it reflects, you do not want your termination to be reflective. Reflectance is measured by how much light (dB) is returned back up the link, and the lower the number (farthest from 0) the better. The ferrule of your termination is the main factor in reflectance, and is categorized in 3 main stages: Physical Contact (PC), Ultra Physical Contact (UPC), and Angled Physical contact (APC). To throw a lot of numbers and letters around, PC polish typically has a reflectance of -30dB, UPC polish typical -40dB, and APC polish -65dB or better. Remember, the lower the number the least amount of reflection, so APC being -65dB is premium performance for optical termination because it returns the least amount of light per termination. Hand polishing connector does rely on skill, an experienced technician will be able to give you the best results but it still can be an imperfect science. Mechanical connectors allowed anybody to be able to put on a connector with the use of specific tools and simple termination procedures, but because of the reflectance of the matching gel, along with the mating of the ferrules, you will achieve around the -40dB referenced above. By being able to fusion splice a factory terminated pigtail to a field fiber, you achieve maximum performance of the ferrule polish due to the low reflectance fusion splice technology. A -65dB return loss on an APC termination is possible because a typical core alignment fusion splice is actually considered a non-reflective event. As we bring fiber closer and closer to the home, with lab environment transmission of 400gB of data over fiber, we can’t afford the return of light that our networks of days past allowed us.
With fusion splicing becoming the termination method of choice for performance, it’s now about installation and how we can make it easier. Pigtail splicing while practical, can be cumbersome with cable management and could require more rack space for that management. You prep your field fiber, you prep your pigtail, you splice them together and manage the slack, and you have a high performing termination.
The industry is now seeing Splice on Connectors as a popular choice of termination vs traditional pigtails because of the cost, space, and time savings they offer. Now you can use a factory terminated connector that can be spliced right at the end of your trunk cable, allowing a time savings in cable prep, a space saving without the excess length of traditional pigtails, and still giving your connection an Insertion Loss as low as .20dB, and a minimal return loss as low as -65dB. Splice on Connectors can arguably be your lowest cost, easiest to install, and best performing termination method.
In conclusion, I want to say that I am writing on my laptop while streaming a basketball game, my wife is streaming her reality TV while scrolling home improvement blogs on her phone, and our demand for bandwidth isn’t slowing down. As our use of technology evolves, so must our data networks. And in terms of how we terminate our fibers, the practice of using splice on connectors has us all trending in the right direction.
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